Automatic phonograph



v June 23, 1942. R. s. CRNMER C l 2,287,726

` AUToMgTic PHONOGRAPH Filed Ag. '21, 1941 l Z-veviior.

atenten .tra 23, 1942 s'm'rsf 2,287,726 y AU'EOMA'REC` PHONQGRPH Richard S. Cranmer, Philadelphia, Pa., assigner to Philco Radio and Television Corporation, Philadelphia, Pa., a corporation of Delaware application august 2i, i941, serai No. 407,787

8 Claims.

out of the reproducing grooves into a spiral of greater pitch, or an eccentric groove; or in the event that the tone-arm moves too rapidly at anytime during the playing of a recording. By wayv of example, the trip itself may be of the type which is triggered by the more rapid than normal movement of the pickup and which, in

adapted to lift the pickup and swing it oi the record', in order that a succeeding recording may be placed upon the turntable.

Many of the trip mechanisms of this general character, which have been employed heretofore, have been of a more or less complicated nature, embodying a large number of moving parts. The use of many parts not only raises the manufacturing cost of the trip mechanism, but has an additional disadvantage in that the trip mechanism, normally in operation, requires considerable energy for its actuation. lThis energy-must come fromN the movement of the tone-arm, which movement is, in turn, brought about by the cooperation between the stylus and the record groove. Thus, it can be seen, especially with the very light stylus pressures now in use, that there may be atendency toward bad tracking, that is, the needle point will often ride up one side of the groove and thereby distort the recorded signal.

'I'he principal object of the present invention is to overcome the aforesaid difficulties by the provision of a tripmechanism which is` simple to manufacture, 'embodies relatively few moving parts, and which requires very little energy to operate its trip restraining means.

A further object of the invention is to provide arnovel trip mechanism of the type' wherein electrical contacts are closed to energize a solenoid or the like which initiates actuation of suitable tone arm moving means.4

A more specific object of the invention is to, provide a trip mechanism of this character anism in elevation, and

v1t turn, serves to trigger a suitable mechanism4 wherein a contact element is'moved by the tone arm in a predetermined path during the playing of a record, a second contact element is disposedTV Y in closely spaced transverse relation to said Y-tationally against an adjustable screw stop I- path, and novel means areA provided for actuat- 55 ing the said contact elements in a manner to elect engagement thereof only when the tone arm moves at a greater than normal rate.

The invention may be fully understood by reference to the accompanying drawing illustrating one form of the invention.

In the drawing:

Figure 1 is avperspective view illustrating the trip mechanism in association with certain elements of a tone arm moving device;

Fig.Y 2 is a sectional view of a phonograph embodying the invention, showing the trip mech- Figs. 3 anda are detail sectional views illustrating a part of the trip mechanism.

Referring to the drawing, there is illustrated inFig, 2 an automatic phonograph comprising the usual turntable I., on which there is disposed a vrecord l2, and the usual tone arm 3 carrying astylus 4 which is adapted to engage the uppermost record on the turntable during the playing thereof. In the specific. device illustrated, the turntable is provided with a peripheral flange 5, thus adapting it to be driven by a motordriven roller (not shown) engaging the said flange. It will be understood, therefore, that the turntableV is rotated at a substantially constant speed during the operation of the phonograph. The turntable I is provided with 'a central hub 6 having a 'depending cam projecarm is mounted on a horizontal pivot B carried by a support which in turn is rotatably mounted in' a hollow bearing structure l0. In accordance with the present invention, the rotatable tone arm support member carries an -extending arm Il which is moved through va predetermined sector about the vertical pivot axis of the tone arm during the record-playing movement of the latter. porting bracket l2 which is insulated from varm Il and has upturned ears i3 supporting a pivot pin It. On the pivot pin there is mounted a contact arm l5 and a frictional roller i6 joined thereto. Thus the `elements l5 and lt constitute a single member rotatably carried by the pivot pin It. At its free end, arm l5 carries a contact element il. The arm is urged gravicarried by bracket l2. Preferably a small piece At its free end, arm ll. carries a sup-` of rubber I9 is provided on arm ii to weight the same and. also to act as a cushion cooperating with the stop i8. A small wire 2d is wound about the pivot pin it and has one end soldered to the contact arm. IB, while its other end is fastened to a terminal lug 2i. This wire serves as an electrical connection to the contact element l1, and it also serves to a small degree as a spring urging arm it against the stop i8.

During the movement of the tone arm while playing a record, the contact element il moves in a predetermined arcuate path. A contact plate 22 is carried by a resilient arm 23 which is mounted upon a stationary part of the phonograph. For example, the arm 2t may be mounted on the under side of the usual base plate. Plate 22 is disposed in closely spaced transverse relation to the path of movement of contact element Il. Moreover, the parts are so designed that as arm Ii moves in the manner above described, the friction roller iti engages the under side of plate 22, as shown in Fig. 4. Contact element il is normally out of engagement with the contact plate, but the rolling engagement oi roller it with plate 22 tends to move arm l5 about the pivot pin lll, thereby moving contact element i'l toward plate 22. At regular intervals, however, plate 22 is pulsed away from contact element il by means of lever 2d which is operated by the cam projection l previously mentioned. Lever 2d is pivoted at 25 and carries a roller 2t at one end Which-rides over the under surface of hub on which thecam projection 1 is provided. At its opposite end, lever 2d carries an adjustable screw or stud 2l which engages the under side of plate 22. Each time the -cam projection l engages roller 26, lever 2d is pivoted counterclockwise, as viewed in Fig. 2, thus raising plate 22 out of engagement with roller I6, and thus permitting arm l5 to drop against its stop Iii. 'I'he parts are so constructed that during the movement o the tone arm at its normal speed, while Iplaying a record, the contact element Il is not moved with suilicient rapidity by roller IG to enable engagement of the said element with plate 22 during the iixed interval between pulsings of the plate. However, when the tone arm moves at a greater than normal speed, as it will when the stylus engages the spiral groove of greater pitch a.. the end oi the record, contact element il is moved upward with suilicient rapidity to cause engagement thereof with plate 22 within the interval between pulsings of the said plate, as shown in Fig. 3. Engagement of. the contact element I'l with plate 22 completes an energizing circuit for solenoid 28. To this end, the elements ll and 22 are connected serially ina simple energizing circuit for the solenoid, as illustrated.

The tone arm moving device whose operation is initiated by the above described trip mechanism may take any suitable form. In the specific illustration of the drawing, there is illustrated one form of tone arm moving device which is fully described and claimed in a copending application of Richard S. Cranmer and Charles Pittman, Serial Number 407,788 led August 21, 1941. This device comprises a rotatable cam plate 29 having gear teeth 30 formed thereon and meshing with an idler gear 3|, which in turn meshes with the gear section 32 of -a slidable clutch member $3 cooperatively associated with the hub 6. The elements 6 and 33 are provided with complementary clutch teeth 34 and 35 which are normally out of engagement, as illustrated.

The solenoid 28 has its armature connected to a lever 3G, which is provided at 3l. Energization of the solenoid rocks the lever 36 clockwise about its pivot, thereby bringing the clutch teeth 34-35 into 'engagement to drive the normal sta- -tionary cam plate 29. At one end, the lever 3E lit arm-moving device.

carries a roller 38 which is normally seated in a recess 39 in a depending flange lil of the cam plate 29. The engagement of the roller and recess maintains the plate 29 in a normal predetermined position. The other end of lever 36 engages clutch member 33, the weight of which normally holds the lever in the position shown.

Upon momentary energi'zation of solenoid 28, the

roller 3B is drawn outof the recess 29 and the clutch teeth are engaged as above described.

Thereafter, roller 3B engages the lower surface of flange il@ and maintains the clutch teeth in engagement until thel cam plate 29 has completed one revolution, at which time roller 38 again enters the recess 39 and the clutch teeth are disengaged.

The upper surface of campla'te 29 is constructed so as to effect the necessary movement of tone arm 3 off of one record and onto the next record. A plate M is secured to arm il by means of a resilient strip l2 so that the plate il may move relative to the arm il. A cam follower in the form of a pin 6E is carried by plate di and engages the cam surfaces of plate 29. A bent rod 64 extends through the hollow tone arm-supporting structure, and the upper 'end of said rod engages a part of the tone arm,

While the lower end thereof seats on plate di. Therefore, when plate 'il is moved vertically by the action of cam plate 29 on the cam follower 43, the tone arm is moved vertically. Horizontal movement of the tone arm is eiected when the cam follower lJ3 engages the cam grooves on cam plate 29. The cam plate is so designed that during a single revolution thereof the tone arm is lifted oi a record, then moved outward to permit changing of records, then moved inward to a position over the marginal portion of the new record, and finally lowered onto the new record.

It will be understood, of course, that any other suitable form of tone arm-moving device may be employed in operative association with the trip mechanism provided by the invention. An example of a solenoid-operated tone arm-moving device which could be employed in conjunction with the present trip mechanism is that illustrated in my copendingl application Serial No. 393,636, flied May 15, 1941. It will be understood, also, that some suitable form of recordchanging apparatus will usually be employed in combination with the trip mechanism and tone In the above-mentioned Cranmer and Pittman application, there is illustrated a suitable form of record-changing apparatus which is actuated by the cam plate 29A shown in the present drawing. However, the present invention is not concerned with the record-changing apparatus.

In accordance with the present invention, there is further provided a manually-operable means for rendering the trip mechanism inoperative whenever it is desired to operate the phonograph manually. AsA illustrated in Fig. 1, such means comprises a lever l5 pivoted at I6 and having one end vunderlying lever 24, while its opposite end-is engaged by a cam element l1 which is agence lever t ina direction to rock lever 2t counterclockwise and lthus move plate 22 out of the path of roller It. Thus, when knob 431s in the -position shown, the plate 22 is maintained in such position that the trip mechanism is inoperative.

While a specific form of the invention has been illustrated for the purpose of disclosure', it will moving said second contactelement out of ensagement with said roller atv time-spaced intervals such that said first contact element is be understood that the invention is not limited by said member and movable thereby in a predetermined path, a second contact element comprising a plane surface positioned in closely spaced parallel relation to said path, means operatively` associated with said first contact element for moving the same-toward said second contact element as the former traverses said path, means for rendering said lastmeans momentarily inoperative at timed intervals such that said first contact element is prevented from engaging said second contact element until the movement of the tone arm exceeds its normal rate, and means operable by the engagement of said contact elements for actuating the tone arm moving means.

2. In an automatic phonograph having a tone arm and means for moving the tone arm from a record-finishing position to a record-commencing position, a trip mechanism for controlling said means comprising a member movable-With said tone arman electricalcontact element carried by said member and movable thereby in a predetermined path, a second contact element comprising a plane surface positioned, in closely spaced parallel relation to said path, said first contact element being biased to a position normally out of engagement with said second contact* element, means operatively associated with said i'lrst contact element and engageable with said second contact element to move said rst contact element toward said second contact element,

means for periodically moving said second contact element out of engagement with said lastnamed means at time-spaced intervals such that said rst contact element is prevented from engaging saidv second Contact y element until the movement ofl the tone arm exceeds its normal rate, and means operable by the engagement of said rst contact element with said second conprevented from engaging said second contact element until the movement of the tone arm eX- ceeds its nor'mal rate, and means operable by the engagement, of said rst contact element with said second contact element for actuating the tone arm moving means. I

4. In an automatic phonograph having 'a tone arm mounted on a vertical pivot and means for moving the tone arm from a record-finishing position to a record-commencing position, a trip mechanism for controlling said means comprising an arm extending radially from the tone arm pivot and movable with the tonev arm, whereby the free end of said radial arm moves rin an arcuate path, a contact plate disposed` in closely spaced parallel relation to said path, a friction roller mounted on the free end of said arm for rolling engagement with. said contact plate, a contact arm attached to said roller and carrying a contact element, said contact arm being rotatable by the rolling engagement of said roller with said contact plate to move the contact element toward the contact plate, means for periodically moving said conact plate out of engagement with said roller at time-spaced intervals such that'said contact element is prevented from engaging said contact plate until the movement of the tone arm exceeds its normal rate, and means operable'by the engagement of said contact element with said contact plate for actuating .the tone arm moving means.

5. In an automatic phonograph having a tone arm and means for moving the tone arm' from tact element for actuating the tone armV moving means. i

'3. In an automatic phonograph having a tone arm and means for moving the tone arm from a record-finishing position to a record-commencing position, a trip mechanism for controlling vsaid means comprising a member movable with said tone arm, an electrical contact arm 'having one Aend pivotally mounted on said member and carrying a contactelement at its free end, a second contact element comprising a plane surface disposed in closely spaced parallel relation to the path of movement of said first contact element,`

said rst contact element being normally out of engagement with said second element, a friction roller mounted on the pivot of-said contact arm and engageable with said second contact element to move said nrst contact element toward said second contact element, means for periodically a record-finishing position to a record-commencing position, a trip mechanism 'for controlling said means, comprising a member movable with said tone arm, an electrical contact element carried by said member and movable thereby in a predetermined path, a second contact element comprising a plane surface positioned in closely spaced parallel relation to said path, said first contact element being normally out of engagement with said second contact element, means operatively associated with said first contact element and engageable with said second contact element to move said rst contact element toward said second contact element, means for periodically moving said second ccntact element out of engagement with said lastnamed means at time-spaced intervals such-that said rst contact element is prevented from engaging said second contact element until the movement of the tone arm exceeds its normal rate, means operable by the engagement of said first contact element with said second contact A element for actuating the tone arm moving means, and manual means operable at will to maintain said second contact element continuously out of engagement with the associated engaging means, thereby to render said trip mechanism inoperative.

6. vIn an automatic phonograph having, a tone arm and. means for moving the tone arm from a record-nishing position to a record `cornmencing position, a trip mechanism for controlling said means comprising a member movable with said tone arm, an electrical contact element carried by said member and movable y thereby in a predetermined path, a second ccntact element comprising a plane surface positioned in closely spaced parallel relation to said path, said rst contact element being normally out of engagement with said second contact element, means operatively associated with Asaid rst contact element and engageable with said second contact element to move saidflrst contact element toward said second contact element, a lever engaging said second contact element and adapted to move the same out of engagement with said last-named means, means for periodically actuating said lever at time-spaced intervals such that said rst contact element is prevented from engaging said second contact element until the movement of the tone arm exceeds its normal rate, means operable by the engagement of said first contact element with said second contact element for actuating the tone arm moving means, a second lever engageable with said rst-named lever to move the same in a direction to maintain said second contact element continuously r\ut of engagement with the associated engaging means, andmanual means for operating said second lever at will, thereby to render said trip mechanism inoperative.

7. In an automatic phonograph having a tonearrn adapted to move across a recording and means for lifting the tone-arm from the recording, a trip mechanism for controlling said lifting means, comprising a switch having relatively movable contact members, means for moving one of said members toward another azswme of said members during the movement of the tone-arm across the recording, means for moving the second member intermittently away from the first member at timed intervals such that the first member is prevented from engaging the second member until the movement of the tone-arm exceeds its normal rate, and means operable by the engagement of said members for initiating operation of said lifting means.

8. In an automatic phonograph having a tonearm and means for moving the tone-arm from a record-nnishng position to a record-counmencing position, a trip mechanism for controlling said means comprising an electrical contact element movable by said tone-arm in a predetermined path during the reproduction of a record, a second contact element positioned in spaced relation to said path, means operatively associated with said first contact element for moving the same toward said second Contact element as the former traverses said path, means for rendering said last means momentarily inoperative at timed intervals such that said rst contact element is prevented from engaging said second Contact element until the movement of the tone-arm exceeds its normal rate, and means operable oy the engagement of said 'contact elements for actuating the tone-arm moving means.

RICHARD s. CRANMER. 

